Inverter-Integrated Electric Compressor

ABSTRACT

Disclosed is a low-cost, inverter-integrated electric compressor with which a high degree of design freedom is maintained, high vibration resistance can be achieved by reliable anchoring of the circuit components, the weight can be reduced easily, and which has excellent operational stability. An inverter-integrated electric compressor has a built-in motor and has a substrate provided with a motor drive circuit including an inverter. In the inverter-integrated electric compressor, after electric components including the substrate have been fixed in a housing space surrounded by a compressor housing and have been assembled, the housing space is filled with an insulating resin, and at least a part of the electric components are sealed by the solidified filling resin. The inverter-integrated electric compressor is characterized in that a resin frame, which has a concave retaining part provided with a concave part formed in a concave shape along the outlines of the circuit components provided on the substrate and has a vent hole provided in the concave retaining part, is mounted on the substrate, and a resin injection space, which can be filled with resin, is formed between the circuit components on the substrate and the resin frame.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an inverter-integrated electric compressor, and specifically relates to an inverter-integrated electric compressor in which its design flexibility is maintained at a high level and in which circuit components can be firmly fixed for a low cost so as to achieve high vibration resistance and excellent operational stability.

BACKGROUND ART OF THE INVENTION

For example, Patent document 1 discloses a structure of an electric compressor which incorporates a motor drive circuit including an inverter, in which the motor drive circuit is coated with a resin mold material, so as to be buried into the resin mold material.

In addition, Patent document 2 discloses a structure where a power semiconductor module placed between a lid and a compressor housing is coated and buried by pouring synthetic insulating resin of a heated fluid state. In the structure disclosed in Patent document 2, whole of the chamber which houses electric components such as a power semiconductor module is filled with resin mold material.

PRIOR ART DOCUMENTS Patent documents

-   Patent document 1: JP2002-70743-A -   Patent document 2: JP4-80554-A

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

However in the above-described conventional structures, because the electric components are fixed substantively by coating resin only, it is difficult for sufficient fixation force to be ensured. Therefore in operation of the compressor, long-time vibration and coating resin hardness decrease in a high-temperature region tend to degrade the fixation force of the coating resin, so that it has been difficult for the electric components to be prevented from being displaced undesirably. Further, even in a case where larger electric components, such as a capacitor, are used in order to improve the inverter function in an inverter-integrated electric compressor, there has been a problem that the thickness of the coating resin decreased substantively and therefore sufficient fixation force cannot be easily ensured.

Furthermore, because the structure is such that the motor drive circuit, etc., is substantively buried, the amount of filled resin or coating resin increases, and by just as much, the electric compressor is blocked from reducing its weight or cost as a whole. An electric compressor used in an automotive air conditioning system in particular is required to be reduced in weight and cost as much as possible.

Therefore an object of the present invention is to provide a low-cost inverter-integrated electric compressor having excellent operation stability, which can achieve a high vibration resistance by firmly fixing circuit components and can be easily reduced in weight while the design flexibility is maintained at a high level.

Means for Solving the Problems

To achieve the above-described object, an inverter-integrated electric compressor according to the present invention is an inverter-integrated electric compressor, incorporating a motor and having a substrate provided with a motor drive circuit including an inverter, wherein after electric components including the substrate have been fixed in a housing space surrounded by a compressor housing and have been assembled, the housing space is filled with an insulating resin, and at least a part of the electric components are sealed by a solidified filling resin, characterized in that a resin frame, which has a concave retaining part provided with a concave part formed in a concave shape along outlines of circuit components provided on the substrate and has a vent hole provided in the concave retaining part, is mounted on the substrate, and a resin injection space, capable of being filled with a resin, is formed between the circuit components on the substrate and the resin frame.

In such an inverter-integrated electric compressor, because the resin is filled in the resin injection space, which is formed around the circuit components on the substrate, so as to prevent the circuit components from vibrating and because the resin frame coating circumference of the resin injection space is mounted on the substrate, the solidified resin which is filled in the resin injection space and the circuit components coated by the resin, can be firmly fixed by the resin frame, so that the vibration is effectively prevented. In addition, the thickness of the resin injection space formed in the resin frame can be set much thinner than that in a conventional case where circuit components are buried by substantively a single resin. Therefore harmful effects of characteristic change of resin material, such as decrease of hardness of coating resin in a high temperature region, can be minimized and fixation force of the circuit components can be ensured and maintained sufficiently, under various operational conditions. Consequently, even when the compressor is operated for a long term, possible undesirable displacement of electric components can be surely suppressed and troubles derived from vibration can be effectively prevented, so as to achieve a compressor which is excellent in operational stability.

Further, members made of resin are excellent in being machined, so as to be formed into various shapes. Therefore a low-cost resin frame corresponding to outlines of conventional circuit components can be easily manufactured, and applications of the present invention make it possible for the design flexibility of a compressor to be maintained at almost the same high level as that of conventional ones without a resin frame. Furthermore, larger circuit components such as a capacitor can be also available as ensuring the fixation force of the circuit components.

Furthermore, a vent hole provided on the resin frame can prevent bubbles from generating and remaining in the resin at the time of filling the resin into resin injection space, so as to achieve fixation of the circuit components more surely.

In the present invention, if the resin frame is made of a material, of which density is less than that of the insulating resin, a further lightweight compressor can be achieved. As described above, because the resin frame is excellent in being machined, the injected amount of the insulating resin can be reduced as increasing the thickness of the resin frame made of low-density resin, so as to achieve a further lightweight compressor easily.

It is preferable that the concave part is formed substantively corresponding to each outline of each of the circuit components on the substrate, though that is not limited. When the resin filled around the circuit components has a nonuniform thickness, a nonuniform force is applied to the circuit components through characteristic change of the resin layer, such as changes of hardness and expansion ratio derived from high temperature, and unexpected tiny displacement of the circuit components arrangement might be caused. On the other hand, when the concave part is formed corresponding to each outline of the circuit components, the resin layer has an almost uniform thickness and therefore the displacement can be minimized, so that the fixation force of the circuit components by the resin layer is stably maintained even in a high-temperature region.

In addition, it is desirable that the concave part is provided with a tapered part, which narrows down the resin injection space toward the vent hole, around the vent hole. Such a tapered dent is formed on the inner surface around the vent hole as narrowing the cross-sectional area of the resin injection space toward the vent hole in the neighborhood of the vent hole. Therefore when the resin is filled in the resin injection space of the concave part, gas such as an air tends to be led into the vent hole, so as to achieve a structure which prevents the air from remaining in the resin. Particularly in a case where the vent hole is formed on an upper base of the concave part, bubbles in the resin can be surfaced to the outside of the resin by a buoyant force, so that the bubbles are effectively prevented from remaining in the resin. Besides, it is not necessary for the tapered part to be formed in all of the concave parts. For example, it is possible for the tapered part to be formed only in concave parts which are formed as corresponding to outlines of aluminium electrolytic capacitors. When the tapered part is formed only in the concave part corresponding to the circuit component such as an aluminium electrolytic capacitor, because its mounted position on the substrate is comparatively high and therefore concave part, which corresponds thereto, tends to leave bubbles, it is possible to efficiently machine for preventing bubbles from remaining.

The kind of the resin filled in the resin injection space is not limited. Therefore it may be the same as the insulating resin filled in the housing space, and alternatively, different resins can be used. When the same resin is used in the resin injection space and the housing space, it is preferable that the insulating resin is filled in the resin injection space and the housing space at the same time, from a viewpoint of reduction of manpower and productive cost.

On the other hand when using another kind of resin different from the insulating resin, the resin filled in the resin injection space is preferably a bonding resin, such as an adhesive agent. It is specifically preferable that it is a bonding resin which has an insulation performance capable of protecting the circuit components on the substrate from defects such as short circuit caused by insufficient insulation, though that is not always necessary. Here, the bonding resin implies a resin which shows declination of the hardness in a high temperature region at a ratio smaller than the insulating resin which is filled in the housing space. Because such a resin changes its hardness little, the fixation force of the circuit component of high temperature is maintained at a level higher than the insulation resin, so that the operational stability of the compressor is improved. Besides, it is preferable that the bonding resin is filled in the resin injection space before the insulating resin is filled in the housing space.

As described above, in a case where the bonding resin is filled in the resin injection space, it is preferable that the resin frame is provided with a hole for positioning a resin injector which injects the bonding resin, though that is not always necessary. Here, it is necessary for the hole for positioning to be configured to promptly place the resin injector which injects the bonding resin at a predetermined position. However, it is not necessary for it to penetrate the resin frame. For example, it is possible that the hole for positioning comprises at least one convex dent which is formed on a surface of the resin frame as corresponding to a shape of a contact section which contacts the resin frame, the contact section being on the resin injector which injects the bonding resin. Such a hole for positioning makes it possible to shorten the time required for the compressor production process, as the injection of the bonding resin is made easy.

It is preferable that the resin frame is provided with a resin injecting hole, though that is not always necessary. In a case where a plurality of the concave parts are provided, it is particularly preferable that each of the plurality of concave parts is provided with the resin injecting hole. Such a resin injecting hole makes it possible to surely achieve the fixation of the circuit components as a tight injection of the resin injection space into the resin injection space is made easy. The resin injecting hole may be the same hole as the vent hole, and alternatively can be another hole.

Even in a case where the resin injecting hole is formed as another hole, like the vent hole, it is preferable that the concave part is provided with a tapered part, which narrows down the resin injection space toward the resin injecting hole, around the resin injecting hole. When the tapered dent is formed on an inner surface around the resin injecting hole, the cross-sectional area of the resin injection space narrows as approaching the resin injecting hole. Therefore when the resin is filled in the resin injection space of the concave part, gas such as air comes to tend to be led to the resin injecting hole, so as to achieve a structure where bubbles are not likely to remain in the resin. Particularly in a case where the resin injecting hole is formed on an upper base of the concave part, bubbles in the resin can be surfaced to the outside of the resin by a buoyant force, so that the bubbles are effectively prevented from remaining in the resin.

The resin frame according to the present invention is preferably mounted on the substrate as fixed to the substrate by fastening, though that is not always necessary. When the resin frame is fastened to the substrate, the displacement of the resin frame from a predetermined position is prevented in filling the resin into the resin injection space or the housing space. Therefore bubble generation or unsuccessful filling process in the resin caused by such a displacement is prevented, so as to surely achieve to fix the circuit components.

Because the inverter-integrated electric compressor according to the present invention can achieve a sure fixation of circuit components at a low cost as keeping the high design flexibility, it is suitable as a compressor for vehicles, where a high vibration resistance is required and its mounting space is strictly limited. It is specifically suitable for a compressor used in an air conditioning system for vehicles, though its application is not limited.

EFFECT ACCORDING TO THE INVENTION

Thus the inverter-integrated electric compressor according to the present invention makes it possible to achieve a high vibration resistance through a sure fixation of the circuit components as keeping its design flexibility at a high level, and therefore a low-cost inverter-integrated electric compressor which can be easily made lightweight and is excellent in its operational stability can be achieved.

BRIEF EXPLANATION OF THE DRAWINGS

FIG. 1 is a FIG. 1 is a schematic longitudinal sectional view of an inverter-integrated electric compressor according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view of a housing space forming part of the inverter-integrated electric compressor in FIG. 1, where FIG. 2 (A) shows a state before mounting a resin frame and FIG. 2 (B) shows a state after mounting the resin frame.

FIG. 3 shows a substrate and a resin frame of the inverter-integrated electric compressor in FIG. 1, where FIG. 3 (A) is a plan view and FIG. 3 (B) is a side view, respectively.

FIG. 4 is an enlarged sectional view of the neighborhood of a concave part of the inverter-integrated electric compressor shown in FIG. 1, where FIG. 4 (A) shows an example of a resin injection space filled with an insulating resin and FIG. 4 (b) shows an example of the resin injection space filled with a bonding resin, respectively.

FIG. 5 shows a modified example of the resin frame shown in FIG. 3, where FIG. 5 (A) is a plan view and FIG. 5 (B) is a partial sectional view, respectively.

FIG. 6 is an enlarged sectional view of the neighborhood of a concave part in a modified example of the resin frame shown in FIG. 3.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

Hereinafter, desirable embodiments will be explained as referring to figures.

FIG. 1 shows an inverter-integrated electric compressor according to an embodiment of the present invention, specifically as an application of the present invention to a scroll-type electric compressor. In FIG. 1, inverter-integrated electric compressor 1 is provided with compression mechanism 2 consisting of fixed scroll 3 and movable scroll 4. Movable scroll 4 can be swung relative to fixed scroll 3 in a condition where its rotation is prevented with ball coupling 5. Motor 7 is incorporated in compressor housing (center housing) 6, and built-in motor 7 drives main shaft 8 (rotation shaft) to rotate. The rotational movement of main shaft 8 is converted into the orbital swinging movement of movable scroll 4, through eccentric pin 9 and eccentric bush 10 which is rotatably engaged therewith. In this embodiment, compressor housing (front housing) 12 is provided with suction port 11 for sucking refrigerant as fluid to be compressed. Sucked refrigerant is led to compression mechanism 2 through a placement part of motor 7. The refrigerant which has been compressed with compression mechanism 2 is delivered to an external circuit, through discharge hole 13, discharge chamber 14 and discharge port 16 which is provided in compressor housing (rear housing) 15.

Housing space 20 is formed by surrounding an extended section of compressor housing 12 (front housing), and motor drive circuit is provided in housing space 20. In more detail, motor drive circuit 21 is provided at the external side of partition wall 22 which is formed in compressor housing 12 against the side of refrigerant suction passageway. Motor drive circuit 21 supplies electricity through seal terminal 23 (an output terminal of motor drive circuit 21), which is attached thereto by penetrating partition wall 22, and lead wire 24 to motor 7, while the refrigerant suction passageway side and the side of motor drive circuit 21 are sealed in the placement part of seal terminal 23. In this embodiment, because motor drive circuit 21 is provided at the external side of partition wall 22, at least one part of electric components including motor drive circuit 21 can be cooled with sucked refrigerant through partition wall 22 by heat exchange. Such a configuration can make a structure simple because electric components, such as high-voltage circuit 25 for motor drive having inverter function, which tend to generate heat can be automatically cooled adequately to maintain a predetermined specification of motor drive circuit 21 without providing another cooling device. In addition, such a configuration is applicable to all types of inverter-integrated electric compressor which compresses refrigerant as a fluid to be compressed, as well as scroll-type electric compressor.

Motor drive circuit 21 includes IPM (Intelligent Power Module) 25 having inverter function and control circuit 26 having a control circuit consisting of circuit components 30, and electric components such as capacitor 27 are provided either integrally with it or separately from it. Motor drive circuit 21 is connected to an external power supply (not shown) through connector 28 as an input terminal. The aperture side to the outside of compressor housing 12, which mounts these electric components including motor drive circuit 21, is covered as sealed with lid member 29, and these electric components are protected by lid member 29.

On substrate 26 having the above-described control circuit, resin frame 31, which has concave retaining sections 32 with concave parts formed like concave shapes along profiles of circuit components, and vent holes 33 formed on concave retaining parts 32, is mounted, so as to form resin injection space 34, into which resin can be filled, between circuit components placed on substrate 26 and resin frame 31. When the resin is filled into resin injection space 34, circuit components 30 can be prevented from vibrating, and generating and remaining of bubbles in the resin can be prevented by vent hole 33, so that circuit components 30 are surely fixed. In addition, resin frame 31 mounted on substrate 26 fixes firmly circuit components 30, and the solidified resin which has been filled into resin injection space 34.

Motor drive circuit 21 and electric components, such as capacitor 27, are placed in housing space 20, resin frame 31 is mounted and then, insulating resin 35 is filled. Solidified insulating resin 35 seals substantively a whole of them. As shown in the figure, the insulating resin is limitedly filled in a minimum range of housing space 20 in view of light weight of compressor 1 as a whole. In addition, if resin frame 31 is made of a material, of which density is less than that of insulating resin 35, a further lightweight compressor can be achieved.

FIG. 2 is a schematic perspective view of housing space 20 of the inverter-integrated electric compressor in FIG. 1, where FIG. 2 (A) shows a state before mounting a resin frame and FIG. 2 (B) shows a state after mounting the resin frame. As shown in FIG. 2 (A), substrate 26 provided with a control circuit consisting of circuit component 30 and noise filter 36 are disposed in housing space 20. IPM 25 disposed under substrate 26 is connected through noise filter 36 to an external power supply, so as to be protected from conductive noises of the signal wire caused by the external power supply.

FIG. 2 (B) shows a state where resin frame 31, which has concave retaining part 32 with a concave part formed like concave shape along the profile of circuit component 30, and vent hole 33 formed on concave retaining part 32, is mounted on substrate 26 shown in FIG. 2 (A). As shown, resin frame 31 is formed as corresponding to the shape of each member including circuit component 30 in housing space 20. Therefore the other members can be mounted without restriction, so that the design flexibility of the compressor is maintained at the same high level as that of conventional ones.

FIG. 3 shows an outline of a condition where resin frame 31 is mounted on substrate 26 in the inverter-integrated electric compressor shown in FIG. 1, where FIG. 3 (A) is a plan view of substrate 26 mounted with resin frame 31 and FIG. 3 (B) is a side view thereof, respectively. Concave part 37, which provides concave retaining part 32 in resin frame 31, has been formed as substantively corresponding to each profile of circuit components 30 on the substrate. Further, because each of concave parts 37 is provided with vent hole 33 which can be used even for filling resin, generating and remaining of bubbles in resin injection space 34 can be effectively prevented while the resin is filled surely into resin injection space 34 corresponding to each concave part 37. The surface of resin frame 31 is provided with positioning hole 38 for resin injector, so that the resin injection process into the resin injection space is easily performed in a short time. Furthermore, because both of resin frame 31 and substrate 26 are provided with fastening section 39, resin frame 31 is mounted on substrate 26 as being fixed to substrate 26 by fastening, so that the displacement of resin frame 31 from a predetermined position is prevented and circuit component 30 is surely fixed.

FIG. 4 is an enlarged sectional view of the neighborhood of concave part 37 of substrate 26 shown in FIG. 3, specifically showing an example where the resin is filled into resin injection space 34 and housing space 20 after mounting resin frame 31 on substrate 26. Besides, FIG. 4 (A) shows a case where insulating resin 35 is filled into resin injection space 34 as well as housing space 20. FIG. 4 (B) shows a case where insulating resin 35 is filled into housing space 20 after bonding resin 40 is filled into resin injection space 34. Because concave part 37 is provided with vent hole 33 which can be used as a hole for filling resin as shown in FIG. 4 (A), resin filling processes into resin injection space 34 and housing space 20 can be performed at the same time, so that the resin filling process can be shortened and the cost can be cut. In addition, bubble generation in resin injection space 34 and housing space 20 or its remaining therein can be effectively prevented by vent hole 33, so as to achieve fixation of circuit component 30 surely.

As shown in FIG. 4 (B), bonding resin 40 is filled into resin injection space 34 through vent hole 33 which can be used as a hole for injecting resin. Because bonding resin 40 shows declination of the hardness in a high temperature region at a ratio smaller than insulating resin 35, fixation force of circuit component 30 in a high temperature is maintained at a level higher than insulating resin 34, so that the operational stability of compressor 1 can be improved. In addition, because concave part 37 almost contacts substrate 26 at substrate facing surface 41, the range of resin injection space 34 filled with bonding resin 40 is limited within the region close to circuit component 30. Therefore the cost can be cut by suppressing the usage of bonding resin 40, and circuit component 30 and resin frame 31 can be firmly fixed with bonding force of bonding resin 40 filled in the limited region.

FIG. 5 shows resin frame 42 as a modified example of resin frame 31 shown in FIG. 3, where FIG. 5 (A) is a plan view and FIG. 5 (B) is a partial sectional view. In resin frame 42, concave part 44, which forms concave retaining part 43, is provided with vent hole 45 capable of being used even as a hole for injecting resin. The inner surface of upper base 46 of concave part 44 is provided with tapered part 48 which narrows down resin injection space 47 toward vent hole 45. Because such tapered part 48 is formed in upper base 46 of concave part 44, it is easy for gas such as air to be vented from resin retaining space 47, so that the bubble is surely prevented from remaining in the filling resin.

FIG. 6 is an enlarged sectional view of substrate 26 shown in FIG. 3 in the neighborhood of concave part 44, specifically showing an example where the resin is filled into resin injection space 47 and housing space 20 after mounting resin frame 42 on substrate 26. Besides, FIG. 6 shows a case where insulating resin 35 is filled into resin injection space 47 as well as housing space 20. Because concave part 44 is provided with vent hole 45 which can be used as a hole for filling resin as shown in FIG. 6, resin filling processes into resin injection space 47 and housing space 20 can be performed at the same time, so that the resin filling process can be shortened and the cost can be cut. In addition, bubble generation in resin injection space 47 and housing space 20 or its remaining therein can be further prevented by tapered part 48 provided around vent hole 45 on upper base 46 of concave part 44, so as to achieve fixation of circuit component 30 surely.

INDUSTRIAL APPLICATIONS OF THE INVENTION

The present invention is applicable to all types of inverter-integrated electric compressor, and specifically suitable for an inverter-integrated electric compressor for automotive air conditioning systems which requires excellent operation stability, excellent vibration durability, high design flexibility and achievement of downsizing and lightweight.

EXPLANATION OF SYMBOLS

-   1: inverter-integrated electric compressor -   2: compression mechanism -   3: fixed scroll -   4: movable scroll -   5: ball coupling -   6: compressor housing (center housing) -   7: motor -   8: main shaft -   9: eccentric pin -   10: eccentric bush -   11: suction port -   12: compressor housing (front housing) -   13: discharge hole -   14: discharge chamber -   15: compressor housing (rear housing) -   16: discharge port -   20: housing space -   21: motor drive circuit -   22: partition wall -   23: seal terminal -   24: lead wire -   25: IPM -   26: substrate -   27: capacitor -   28: connector -   29: lid member -   30: circuit component -   31, 42: resin frame -   32, 43: concave retaining part -   33, 45: vent hole -   34, 47: resin injection space -   35: insulating resin -   36: noise filter -   37, 44: concave part -   38: positioning hole -   39: fastening part -   40: bonding resin -   41: substrate facing surface of concave part -   46: upper base of concave part -   48: tapered part 

1. An inverter-integrated electric compressor, incorporating a motor and having a substrate provided with a motor drive circuit including an inverter, wherein after electric components including said substrate have been fixed in a housing space surrounded by a compressor housing and have been assembled, said housing space is filled with an insulating resin, and at least a part of said electric components are sealed by a solidified filling resin, wherein a resin frame, which has a concave retaining part provided with a concave part formed in a concave shape along outlines of circuit components provided on said substrate and has a vent hole provided in said concave retaining part, is mounted on said substrate, and a resin injection space, capable of being filled with a resin, is formed between said circuit components on said substrate and said resin frame.
 2. The inverter-integrated electric compressor according to claim 1, wherein said concave part is provided with a tapered part, which narrows down said resin injection space toward said vent hole, around said vent hole.
 3. The inverter-integrated electric compressor according to claim 1, wherein said concave part is formed substantively corresponding to each outline of each of said circuit components on said substrate.
 4. The inverter-integrated electric compressor according to claim 1, wherein said insulating resin is filled in said resin injection space and said housing space.
 5. The inverter-integrated electric compressor according to claim 1, wherein said insulating resin is filled in said housing space after a bonding resin is filled in said resin injection space.
 6. The inverter-integrated electric compressor according to claim 5, wherein said resin frame is provided with a hole for positioning a resin injector which injects said bonding resin.
 7. The inverter-integrated electric compressor according to claim 1, wherein said resin frame is provided with a resin injecting hole.
 8. The inverter-integrated electric compressor according to claim 7, wherein each of a plurality of concave parts is provided with said resin injecting hole.
 9. The inverter-integrated electric compressor according to claim 7, wherein said concave part is provided with a tapered part, which narrows down said resin injection space toward said resin injecting hole, around said resin injecting hole.
 10. The inverter-integrated electric compressor according to claim 1, wherein said resin frame mounted on said substrate is fixed to said substrate by fastening.
 11. The inverter-integrated electric compressor according to claim 1, wherein said compressor is mounted on a vehicle.
 12. The inverter-integrated electric compressor according to claim 11, wherein said compressor is one for an air conditioning system for vehicles. 